Various embodiments of the invention relate generally to a MEMS device and particularly to a MEMS device on a printed circuit board (PCB).
As form factors grow smaller with time, so do MEMS devices. The height of MEMS devices, particularly those used as microphones includes not only MEMS and CMOS heights but also the height of a laminate on top of which the MEMS and CMOS chip are built. The laminate is typically 0.25 millimeters (mm), adding to the overall height of the microphone. While this measurement may seem insubstantial, with the size of the microphone being in the order of millimeters, the laminate-associated height increase is indeed substantial.
Also added to the overall height of the microphone is solder which is used to physically connect the laminate to a flexible printed circuit board (PCB). More importantly, due to the presence of a port in the PCB, in microphone applications the solder adds undesirable contamination.
Further, added steps are necessary in building the microphone, often requiring each step to be performed by a different manufacturer. For example, a manufacturer may build the MEMS chip, the CMOS chip, and the laminate, and provide the same as one module to another manufacturer. The second manufacturer can then mount the module onto a PCB, along with forming passive elements on the PCB. Additional steps during manufacturing are inherently undesirable.
Thus, height, contamination and extra manufacturing step(s) are currently experienced limitations in building a MEMS device, such as a microphone.
What is needed is a MEMS device with improved form factor, reduced contamination, and ease of manufacturing.